bet sub sonic combo for 500 yards ?

been looking into a lot of sub sonic info lately . What would be the best combo for lobbing heavy pills out to 500 yards or so for steel ? looking at this bullet
for the 458 socom GS CUSTOM BULLETS - 458566SP195 Technical Data
only thing I read that a longer throat would affect accuracy if you wanted to shoot factory ammo . also in a bolt gun is there any problems pushing the socom past 35k psi if you wanted ? I was interested in the 520 whisper but I read it wont feed from a aics mag because of the .510 bullets ? according to gs that 566gr bullet can be load with the length of the 458 socom case to a oal of 2.825

thought about it but I read wind is hell on the 300 blkout at 500.
I think it drifts 9 moa with a 10 mph crosswind . from what I read getting
barrels for the socom is a pain in the @$$ . looked at something short like the 450 marlin but it would need a long action for the feeding from a dbm. a lot of the chassis I like are short action only right now becaue their filling those orders first before making a run of long actions chassis in rem 700. I asked ssk about the 510 whisper to see if they had brass for it. its impressive with the amax out to 500 yards

probably any of the 35s would 338 federal etc but I want something different and big. ssk just got back to me they said brass for the whisper is 5.50$ a case from lapua brass. though they may have meant 5.55$ a cartridge because she said a round not a case .